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Revision as of 19:15, 24 November 2001 by Wayne Hardman (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)The Great Comet of 1997, Comet Hale-Bopp (C/1995 O1)
Discovered at an incredible 7.1AU from the Sun, prediscovey images were found showing the comet at a frankly absurd 13AU from the Sun! This was quickly noted to be remarkable. The comet was very active at these distances, but would it hold up?
Many comets have large outbursts at great distance only to quieten down. Hale-Bopp did not. It reached naked eye visibility at 2AU from the Sun and just continued to brighten.
If it had passed as close to Earth as Comet Hyakutake (C/1996 B2) did in 1996, then the comet's tail would have spanned the entire sky and it would have been brighter than a full moon. Sadly, it made a closest approach to Earth that would have rendered many lesser comets totally invisible and still spanned half the sky with it's two tails, although the longest reaches of the tail were too faint to be visible. It's nucleus was a gargantuan 50km in diameter, nearly three times the size of Comet Halley.
The first naked-eye observation was on May 20, 1996 and a December 1997 naked-eye observation means the comet remained visible without aid for 569 days, or about 18 and a half months! The previous record had been set by the Great Comet of 1811, which was about 9 months.
The comet probably made it's last perihelion 4200 years ago, following the 1997 perihelion passage, it will next return to the inner solar system 2380 years later as, no doubt, another spectacular comet to be traced back to the ancient texts of which you've just finished reading one.